peck’s (1969) observational method – eight …2015/07/16 · vision: • enable step changes in...
TRANSCRIPT
2015/7/22
1
「リスク共生から見た地盤工学上の課題」
地盤工学の新たなる課題とモニタリングの重要性
ケンブリッジ大学、横浜国立大
曽我健一
社会インフラストラクチャーリスク共生、イギリスでは。。。
• 外貨獲得のためのインフラ開発
• データに基づいた政策決定
• Building Information Modellingの活用
• リスクベースの維持管理
• 工学的知識を活用したモニタリング
Establishment of
“Infrastructure UK” in 2010
From 2010 to 2014
トンネル!
National Infrastructure Plan
• “High quality infrastructure is essential for supporting
productivity growth. Delivering the right infrastructure at
a local, regional and national level, across the UK, is […]
key to the government’s long-term economic plan.”
• £466B (90兆円)for the next generation of infrastructure
by 2020
• 2,500 different projects
• A step-change in the nation’s approach to infrastructure
investment.
• An export potential for an international market that is
valued at least $57 trillion (5700兆円)in the period up
to 2030.
118 km from east to west
37 stations
9 new stations (8 sub-surface)
Increase London's rail-network
capacity by 10%
Crossrail – New London Underground Line in London Industrial Strategy (2013)
過大設計安全率の神話化
品質向上
建設材を少なく。 他にない地盤工学
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UK Infrastructure - Risk
• The cost to the nation of inadequate infrastructure is estimated to be in
the order £2M per day or $0.75B per year.
• For extreme events, direct costs can be in the £100Ms per incident.
• National economic infrastructure is largely privatized and sectorally
divided.
• As foreign investment in infrastructure systems and networks
increases, trans-national corporate governance priorities may also
come into conflict with these national hierarchies, with fiscal and
political consequences.
Evidence base decision making
Building Information Modelling
London Underground
Victoria Station UpgradeBuilding Information Modelling
(courtesy Mott MacDonald)
D B
11
Tottenham Court Road (TCR)-STATION UPGRADE PROJECT
Northern Line
Central Line
Source: Halcrow
新しいインフラと古いインフラ
• 新しいインフラ– 建設および維持管理を安く
– 本当のパフォーマンスとは。
– Observational method
– 長期モニタリング、そして劣化モデルの構築
• 古いインフラ– 実際の挙動を示したデータが必要
– 他のシステムとの相互作用から検討
– 劣化モデルの構築
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Observational Method
UK Design Codes - Soil Strength Parameters
mo
de
rate
ly c
on
se
rva
tiv
e
Soil Strength Parameter Results
No
of
Re
ad
ing
s
1 in 21 in 201 in 1000
Mo
st
Pro
ba
ble
Ch
ara
cte
ris
tic
ma
teri
al
pro
pe
rty
(us
ed
in
str
uc
tura
l e
ng
ine
eri
ng
)
Mo
st
Un
fav
ou
rab
le
(Eg Undrained strength, SPT etc)
PeckPeck EC
EC
14
15
CIRIA (1999) Report 185 - Nicholson, Tse and Penny
Goals
• Clarify OM definition and process
• Integrate OM process into modern design
• Focus on “Ab Initio” applications – better planning
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Ideal EC7 Predicted versus Measured Performance
No
. o
f re
ad
ing
s
Deflection ( )
"Ideal" distribution of
measured deflections
Predicted EC7
Characteristic
Value (SLS)
5%
Predicted most
probable value
Most
Unfavourable(ULS)
16
Ideal EC7 Predicted versus Measured Performance
No
. o
f re
ad
ing
s
Deflection ( )
"Ideal" distribution of
measured deflections
Predicted EC7
Characteristic
Value (SLS)
5%
Predicted most
probable value
GREENAMBER
RED
Most
Unfavourable(ULS)
Trigger
implement
17 18
CIRIA (1999) Fig 3.13 Multi Stage Excavation
18
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CIRIA (1999) R185 Figure 1.2
The OM Process
21
Monitoring Dashboard Data Interpretation Optimisation - DashboardsNorthern Line Monitoring at Liverpool Street Station
Monitored Section of the Royal Mail Tunnel
Crossrail – Liverpool Street Station – C510
Monitored SectionCrossrail
Platform
Tunnel
Excavation
Bloomfield
Box
Excavation
After Crossrail
How Big Is It?
≈ 2.74 m
≈11 m
≈6 m
Constructed: 1917 - 1923
Suspended: 2003
Made of cast iron
2015/7/22
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Tunnelling Induced Greenfield Settlements
Smax
Longitudinal Settlement
Longitudinal Strain
Tension
Compression
(After Attewell, 1986)
Bending
Mode
Shear
Mode
After Devriendt
Shear LPDT Orientation
Expected settlement profile
New
Tunnel
Compressive (-ve) when ring nearest
tunnelling approach shifts downward
with respect to neighbouring ring!
Data for these sensors
above sign reversed in
data processing.
Layout of Sensors & Location of
Sensors 11, 34-40
Data presented
2881
@ Node 11
2940
@ Node 40
29.5m
New Tunne
l
120 Wireless Sensors to monitor
movements of 60 joints
Wilcock
Pilot tunnel
Main tunnel
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百聞は一見に如かず
The ‘Smart Tunnel’
A building
construction at the
Isle of Dog,
London
Loizos Pelecanos
36 Pile load testing – current trends and innovative monitoring
River Terrace Deposits
Lambeth Group
Thanet Sand
Chalk
Made Ground / Alluvium
Large diameter piles - 2.4m dia.
Very deep - avoid tunnels
( 25m into Chalk)
LU tunnel
Thick raft span over tunnels
LU tunnel
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Reinforcement
cage
1
2
43
NFibre optic
cable cluster
Regiment 2
O-Cell
Regiment 1
Pile
Typical SectionElevation
BOTDR analyser• Distance range ≈10-30km• Readout resolution = 0.05m• Gauge length resolution = 0.2-1m• Strain Resolution = 10-30me
Distributed Brillouin Sensing
Providing “Continuous Strain Profile”
Layer 1
Layer 2
O-Cell
PileLoad distribution
Compression
Friction
DownUp
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Integrated FO
distributed strain
and can provide
distributed values
of vertical
displacement
This shows the
evolution of vertical
displacement with
applied load at
every point along
the pile depth
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
0 0.01 0.02 0.03 0.04
Ele
va
tio
n [
m]
Vertical displacement, u [m]
Vertical Displacement Profiles
P=0
P=1.78MN
P=3.64MN
P=5.92MN
P=6.93MN
P=8.58MN
P=10.53MN
P=12.21MN
P=13.72MN
P=15.51MN
P=17.29MN
P=18.94MN
P=20.51MN
P=22.43MN
P=23.94MN
P=25.56MN
Load (MN)
Dis
pla
cem
ent
(mm
)
Load (MN)
Load (MN)
Dis
pla
cem
ent
(mm
)
Load (MN)
Load (MN)
Dis
pla
cem
ent
(mm
)
Load (MN)
Top of O-cells
Level 2
Level 3
Level 4
Level 5
Level 6(highest)
Fibre optic integrated strain
Extensometers
Displacements are relative to the top of the pile
Small displacement
Very small displacement
Fibre optic displacement
from integration of strain
Good agreement between
fibre optic and
extensometers for all
levels, even for small
displacements at higher
levels
• Split soil into 4 layers:
> Layer 1: Made Ground
> Layer 2: Sandy Silty Clay
> Layer 3: Thanet Sand
> Layer 4: Chalk
• Calculate:
(a) Shaft Friction
(b) Vertical Displacements
48
Further post-processing:
49
-50
0
50
100
150
200
0 0.005 0.01 0.015 0.02 0.025 0.03
Shaf
t Fr
icti
on
, SF
[kP
a]
Displacement, z [m]
1. Made Groundc31
c32
c41
c42
0
20
40
60
80
100
120
140
160
180
200
0 0.005 0.01 0.015 0.02 0.025 0.03
Shaf
t Fr
icti
on
, SF
[kP
a]
Displacement, z [m]
2. Sandy Silty Clay
0
20
40
60
80
100
120
140
160
180
200
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035
Shaf
t Fr
icti
on
, SF
[kP
a]
Displacement, z [m]
3. Thanet Sand
-800
-600
-400
-200
0
200
400
600
0 0.01 0.02 0.03 0.04
Shaf
t Ft
icti
on
, SF
[kP
a]
Displacement, z [m]
4. Chalk
Image Source: Pile Dynamics and National Highway Institute
PROBLEMS WITH PILE CONSTRUCTION
Construction can be challenging – alignment, concrete quality and placement, soil collapse
Visible inspection not possible
Repair and rework is very difficult
Not all anomalies are defects/detrimental
2015/7/22
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-5
0
5
10
15
20
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Tem
per
atur
e C
han
ge (°C
)
Days
DFOS temperature over time at 15m depth (-8.7 mOD)
mOD) T-1-1 Green
T-2-1 Orange
-5
0
5
10
15
20
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Tem
per
atur
e C
han
ge (°C
)
Days
DFOS temperature over time at 35m depth (-28.7 mOD)
T-1-1 Green
T-2-1 Orange
TEMPERATURE AT A GIVEN DEPTH OVER TIME
DIFFERENTIAL TEMPERATURE AT 14 HOURS
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5
-5 0 5 10 15 20 25
Dept
h (m
OD
)
Temperature Change ( C)
14 Hours (Heating)
T-4-1T-3-1T-2-1T-1-1O-Cell
1
2
43
Cooler
Warmer
N
1
2
43
Warmer
Cooler
Value =Product
(what it claims it will
do)
+Confidence
in delivery(do I believe it will work?)
Mission:
“Transform the future of infrastructure through smarter information”
Vision:• Enable step changes in construction practice• Establish a world-leading sensing and monitoring industry • Extend asset life & reduce management costs
An Innovation and Knowledge Centre
Funded by EPSRC and Innovate UK
17 Million pounds investment for five years from UK government and Industry
Consultants, contractors and asset managers
Technology and information supply chain
Knowledge partners
Infrastructure Clients(Owners and Operators)
2015/7/22
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Field demonstrations & case studiesExamples of Monitoring Applications
Piles
Examples of Monitoring Applications
Masonry Arches
Lee Tunnel, Abbey Mills, Stratford – Shaft F
Winner of the 2013 Fleming Award: MVB JV, CH2M Hill, AECOM, Bachy Soletanche, Underground
Professional Services, University of Cambridge, Mott MacDonald, WJ Groundwater and ESi
2015/7/22
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Examples of Monitoring ApplicationsTunnels
社会インフラストラクチャー
• インフラストラクチャーの社会の役割。
• データに基づいた意志決定、Building Information
Modellingの活用。
• Observational Methodなどリスクを考慮した設計、施工、維持管理。
• 工学的知識を活用したモニタリング。その中での地盤工学者の役割。